JERSEY-1429: Grizzly containers - unified context path handling.

Grizzly doesn't support setting context path to more than one path segment, which is most likely correct
from the context path definition in servlet spec (see GRIZZLY-1481 for additinal details). Patch fixed
this in terms of documentation - only first path segment will be used when creating grizzly http or
servlet container.

Change-Id: I10079a8c30d58208972b4c17b423a33fe82a74bb
Merge "JERSEY-1429: Grizzly containers - unified context path handling."